Introduction

Here I am performing simple save, delete, search and update operations in a Windows Forms Application using the SqlParameter class. The SqlParamater class is found in the "System.Data.SqlClient" namespace. It is a class of a connected architecture of .NET framework. It represents parameters. We use the SqlParameter class to perform various operations.

Open Visual Studio 2010 and create a Windows Forms Application. Add some UI Controls and arrange them like in the following figure.



Write the following code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace sqlparamater
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
SqlConnection conn;
SqlCommand comm;
string connstr = "database=student;server=.;user=sa;password=wintellect";
private void btnsave_Click(object sender, EventArgs e)
{
conn = new SqlConnection(connstr);
comm = new SqlCommand();
conn.Open();
// creating instance of SsqlParameter
SqlParameter rollno=new SqlParameter("@rn",SqlDbType.Int);
SqlParameter name = new SqlParameter("@n", SqlDbType.VarChar);
SqlParameter course = new SqlParameter("@c", SqlDbType.VarChar);
SqlParameter city = new SqlParameter("@ci", SqlDbType.VarChar);
// Adding parameter to SqlCommand
comm.Parameters.Add(rollno);
comm.Parameters.Add(name);
comm.Parameters.Add(course);
comm.Parameters.Add(city);
// Setting values
rollno.Value = Convert.ToInt32(txtrollno.Text);
name.Value = txtname.Text;
course.Value = txtcourse.Text;
city.Value = txtcity.Text;
// adding connection to SqlCommand
comm.Connection = conn;
// Sql Statement
comm.CommandText = "insert into student_detail values(@rn,@n,@c,@ci)";

try
{
comm.ExecuteNonQuery();
MessageBox.Show("Saved");
txtcity.Clear();
txtcourse.Clear();
txtname.Clear();
txtrollno.Clear();
}
catch (Exception)
{
MessageBox.Show("Not Saved");
}
finally
{
conn.Close();
}
}
private void btndelete_Click(object sender, EventArgs e)
{
conn = new SqlConnection(connstr);
comm = new SqlCommand();
conn.Open();

SqlParameter rollno = new SqlParameter("@rn", SqlDbType.Int);

comm.Parameters.Add(rollno);

rollno.Value = Convert.ToInt32(txtrollno.Text);


comm.Connection = conn;
comm.CommandText = "delete from student_detail where rollno=@rn";

try
{
comm.ExecuteNonQuery();
MessageBox.Show("Deleted....");

txtcity.Clear();
txtcourse.Clear();
txtname.Clear();
txtrollno.Clear();
txtrollno.Focus();

}
catch (Exception)
{
MessageBox.Show("Not Deleted....");
}
finally
{
conn.Close();
}
}

private void btnsearch_Click(object sender, EventArgs e)
{
if (txtrollno.Text == "")
{
MessageBox.Show("Please, Enter Roll No. of Student");
}
else
{
conn = new SqlConnection(connstr);
comm = new SqlCommand();
conn.Open();

SqlParameter rollno = new SqlParameter("@rn", SqlDbType.Int);
SqlParameter name = new SqlParameter("@n", SqlDbType.VarChar);
SqlParameter course = new SqlParameter("@c", SqlDbType.VarChar);
SqlParameter city = new SqlParameter("@ci", SqlDbType.VarChar);

comm.Parameters.Add(rollno);
comm.Parameters.Add(name);
comm.Parameters.Add(course);
comm.Parameters.Add(city);
rollno.Direction = ParameterDirection.Input;
name.Direction = ParameterDirection.Output;
course.Direction = ParameterDirection.Output;
city.Direction = ParameterDirection.Output;

name.Size = 30;
course.Size = 20;
city.Size = 20;

rollno.Value = Convert.ToInt32(txtrollno.Text);


comm.Connection = conn;
comm.CommandText = "select @n=name,@c=course,@ci=city from student_detail where rollno=@rn";

try
{
comm.ExecuteNonQuery();
txtname.Text = name.Value.ToString();
txtcourse.Text = course.Value.ToString();
txtcity.Text = city.Value.ToString();

}
catch (Exception)
{
MessageBox.Show("Not Found");
}
finally
{
conn.Close();
}
}
}
private void btnupdate_Click(object sender, EventArgs e)
{
conn = new SqlConnection(connstr);
comm = new SqlCommand();
conn.Open();
SqlParameter rollno = new SqlParameter("@rn", SqlDbType.Int);
SqlParameter name = new SqlParameter("@n", SqlDbType.VarChar);
SqlParameter course = new SqlParameter("@c", SqlDbType.VarChar);
SqlParameter city = new SqlParameter("@ci", SqlDbType.VarChar);

comm.Parameters.Add(rollno);
comm.Parameters.Add(name);
comm.Parameters.Add(course);
comm.Parameters.Add(city);